WHAT IT MEANSHIV, or human immunodeficiency virus, is the virus that causes the disease called AIDS, or acquired immunodeficiency syndrome. You can see that both medical terms share the word immunodeficiency, a mouthful of a word that means deficiency of the immune system. This explains exactly why having an HIV infection threatens your health—it can weaken your body’s own natural defense against sickness.

WHY IT MATTERSThe longer HIV attacks your immune system, the more you risk developing serious infections and cancers. To prevent this from happening, it is important to get tested for HIV—and, if necessary, start treatment with HIV medication—as soon as possible. If you do come down with something serious or if blood tests show that your immune system is low on power, your diagnosis officially changes from “HIV positive” to “AIDS.”

HIV? Or AIDS? HIV and AIDS are not the same thing, though many people wrongly use the terms as if they were. Over the past decade, as better drugs have increasingly made this disease manageable for many years, the conventional wisdom that HIV infection always leads to sickness and an AIDS diagnosis has had to be revised.

NOTE TO ROOKIES Never forget these two facts: First, you can live a long, healthy life with HIV. Second, learning as much as you can about HIV and getting to know other people who have it are the best defense against sickness.